Blade lock



Feb. 14, 1961 BLADE LOCK Filed Nov. 21, 1957 J. SZYDLOWSKI 2,971,744

United States Pate t F BLADE LOCK Joseph Szydlowski, Bordes (Basses-Pyrenees), France .Filed Nov. 21, 1957, Ser. No. 697,970 7 Claims priority, application France Nov. 27, 1956 6 Claims. 01. 253-11 The present invention relates to a device for fastening and locking in position rotor blades of turbines, compressors and like machines, this device being adapted to prevent the blades constituting the bladings of these machines from moving in a direction parallel to their axes, these blades being inserted by construction on the rotor. In most cases the root portion of each blade is provided with longitudinal ribs engaging corresponding or conjugate grooves formed in the rotor wheel. eificient and reliable locking means must be provided to prevent the blades from moving in a direction parallel to the rotor axis.

Now it is the object of this invention to provide a device for fastening and locking rotor blades of turbines, compressors and like machines which are fastened on the rotor through a series of longitudinal conjugate ribs and grooves respectively formed on the blade roots and in the rotor-wheel, characterized in that it comprises two superposed strip pins disposed in a longitudinal bottom groove formed in the rotor wheel beneath the blade fastening grooves, these two pins having one of their ends bent at right angles and co-acting with a pair of flat washers engaging the adjacent, abreast lateral walls of the blade roots and rotor wheel on either side of said blade roots and rotor wheel, said bent ends being respectively directed in reverse directions while the other ends of the strip pins are bent at right angles after the strip pins and washers have been fitted in position.

In order to afiord a clearer understanding of the present invention and of the manner in which the same may be carried out in the practice, reference will now be made to the accompanying drawing forming part of this specification and illustrating diagrammatically by way of example a typical embodiment of the invention. In the drawings: 1

Fig. 1 is a lateral view showing on a relatively large scale one peripheral portion of a rotor wheel in which spaced recesses formed with corrugated longitudinal grooves are provided, one recess being empty, the next recess containing a blade without fastening means, the last recess containing a blade fastened and locked according to this invention.

Fig. 2 is a section taken upon the line 11-11 of Fig. 1.

Fig. 3 is a perspective view of a strip pin of the locking device according to this invention.

Fig. 4 is another perspective view of a flat washer of the locking device of this invention.

Fig. 5 is another perspective view showing a modified embodiment of a lock pin according to this invention.

Fig. 6 is an external view showing a blade mounted on a rotor wheel and formed with a mounting groove according to a modified embodiment.

The rotor 1 in Figs. 1 and 2 of the drawing is formed along its outer periphery with a series of spaced longitudinal corrugated grooves 3 of the fir-tree type for mounting each blade 2. Underlying each corrugated groove is a bottom groove 4 formed in the rotor material.

In this case some 2,971,744 Paten ed Feb. 14, real.

The blade 2 has a root portion 5 formed with longitudinal ribs 30 corresponding to the grooves 3; these root portions 5 are inserted by a longitudinal sliding movement in the corrugated grooves '33 of rotor 1, the bottom groove 4 under the lower face of the root remaining free.

In thisbottom groove are inserted a pair of superposed strip pins 6'having a head-forming portion 7 bent at right angles thereto, the two heads 7 of the pair of strip pins being opposite to each other. A fiat washer 8 is disposed be tween the heads 7 and the registering faces of the rotor 1 and blade 2. On the'straight end portions of the strip pins 6 another fiat washer 8 engaging the other registering faces of the rotor l andblade 2 is fitted, wherea'fter the projecting ends of the strippins are flanged at 9 against the other washer 8, as shown in Fig. 2. Thus, the blade 2 is locked against longitudinal displacement relative to the rotor 1 in an efiicient and reliable manner.

Other pin sections, for example a semicircular or segmental section 6a of Fig. 5, may be substituted for the flat or rectangular section shown in Fig. 3. Besides, any other pin section consistent with the cross-sectional shape of the bottom groove 4 may be resorted to; besides, hollow pins may be used, if desired.

The above-described locking devices described in connection with corrugated grooves of the fir-tree type and correspondingly shaped blade roots may also be used in blade fastenings utilizing grooves of different design, for example grooves of the dovetail or keyhole types or those illustrated at 10 in Fig. 6 for ablade 2a fitting in the rotor 1a, a bottom groove 4a being formed in the root-receiving groove for inserting the locking pins there- 1n.

Of course, many modifications may be brought to the device described herein without departingfrom the'scope of the invention as set forth in the appended claims.

What I claim is:

1. Blade lock, notably for rotor blades of turbines, compressors and like machines which are fastened on the rotor wheel through a series of longitudinal conjugate ribs and grooves respectively formed on the blade roots and in the rotor wheel, comprising, in combination, for each blade, two fiat washers respectively engaging the adjacent registering lateral walls of the blade root and rotor wheel on either side of said blade root and rotor wheel, and two pins in contacting engagement extending through said washers and through a longitudinal bottom groove formed in the rotor wheel beneath the blade fastening groove and having the shape of the washer hole, said pins having heads at their their ends to abut parts of the washers, the two heads abutting the same washer being opposite to each other.

2. Blade lock, according to claim 1, wherein each pin is solid.

3. Blade lock, according to claim 1, wherein each pin is hollow.

4. Blade lock, according to claim 1, wherein each pin is formed with a flat face for permitting its contacting engagement with the other pin.

5. Blade lock, notably for-rotor blades of turbines, compressors and like machines which are fasteneed on the rotor wheel through a series of longitudinal conjugate ribs and grooves respectively formed on the blade roots and in the rotor wheel, comprising, in combination, for each blade, two fiat washers respectively engaging the adjacent registering lateral walls of the blade root and rotor wheel on either side of said blade root and rotor Wheel, and two pins in contacting engagement extending through said washers and through a longitudinal bottom groove formed in the rotor wheel beneath-the blade fastening groove and having the shape of the washer hole, said pins being respectively formed with two heads bent at right angles and directed in opposite direction to abut parts of angles to. abut parts of s'aid other washer.

6. Blade; lock, notably for rotor bladesxof'turbinies,

' compressors and like machines which are fastened on the .rotor wheel through a series of longitudinal'conjugate ribs andgrooyes respectively formed on the blade roots 'and'in the rotor wheel, comprising, in combination, for

each blade, two fiat washers respectively'engaging' the adjacent registering lateral walls of the bladeroot and rotor wheel" on either side of said blade root and rotor wheel,

and two radially superposed pins extending through said f washers andthrough a longitudinal bottom groove'formed in the rotor wheel beneath the-blade fastening groove and havingthesha'pe-of the washer hole, said pins being respectively formed with two heads bent 'at right angles and radially directed in opposite directions to abut, radially aligned parts of one of said ,washers, the straight portions of said pins having their ends projecting beyond the other washer, said ends being deformable whereby they may be bent at right angles to abut radially aligned parts of said other washer.

References in the fi le of this patent UNITED STATES PATENTS 786,648 Ledwith Mar. 26, 1957 FOREIGN PATENTS 672,401 Great Britain May 21-, 1952 691,380 Great Britain May 13, 1953 715,837 Great Britain Sept. 22, 1954 747,098 Great Britain Mar. 28, 1956 

